Death wobble!?

biketeacherdave said:

this vibration in the passenger seat at about the same speed was my front prop ujs

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Thanks Dave, but all done, both UJs Front and rear props, bit of a mystery, posted a thread on it way back, still not cured

Today I got the violent wobble again on a left turn at around 85 Kph. Not as violent as before but still...
I'm going to try and replace the track rods this weekend and see what will happen.
I just might do the front brakes as well.

Tilo said:

Today I got the violent wobble again on a left turn at around 85 Kph. Not as violent as before but still...
I'm going to try and replace the track rods this weekend and see what will happen.
I just might do the front brakes as well.

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Sorry to hear that Tilo, what sort of steering damper did you fit? I think it has to be a genuine Land Rover or a bilstein.

I think the fact that your car is on springs may make it a little more susceptible to this issue, I have Terrafirma shocks on mine which are stiffer than the original boge all this adds to the mix

I think it's a good idea to get the steering track rods and drag links replaced

Tilo said:

Today I got the violent wobble again on a left turn at around 85 Kph. Not as violent as before but still...
I'm going to try and replace the track rods this weekend and see what will happen.
I just might do the front brakes as well.

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The chances are that the complement that is causing the issue has been put more into play by the replacement of what was left of the rubber bushes with the unforgiving poly bushes.

I would personally always have rubber bushes in the panhard as the extra little bit of damping they give is beneficial. Again, I'd use rubbers for the steering damper.

You may have play in the track rod ends but and you mention brakes but the next step has to be to check the pre load on the swivels. If you've been running for a long time with shot bushes or steering damper then you may have kicked the wear down the line making swivel pins the next most likely culprit.

This is assuming that tyres are matched and in good nick and likewise with dampers but generally that wobble is triggered by play in the steering and if you've replaced panhard bushes and steering damper then it's the swivel pins that need to be checked next to see whether you need to whip out a shim or two.

Horse_Apple said:

The chances are that the complement that is causing the issue has been put more into play by the replacement of what was left of the rubber bushes with the unforgiving poly bushes.

I would personally always have rubber bushes in the panhard as the extra little bit of damping they give is beneficial. Again, I'd use rubbers for the steering damper.

You may have play in the track rod ends but and you mention brakes but the next step has to be to check the pre load on the swivels. If you've been running for a long time with shot bushes or steering damper then you may have kicked the wear down the line making swivel pins the next most likely culprit.

This is assuming that tyres are matched and in good nick and likewise with dampers but generally that wobble is triggered by play in the steering and if you've replaced panhard bushes and steering damper then it's the swivel pins that need to be checked next to see whether you need to whip out a shim or two.

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There is no pre load to set on P38 swivel hubs.

Ok, here's a quick summary from start till now:

Apart from the front tires starting to get worn out on the outside, the car was driving fine, no vibrations. I knew I had to replace the radius arm bushes as they were completely gone. Decided to go for the Britpart DC7107 poly bush kit and replace all suspension bushes. After replacing these, car gets a violent wobble at around 85-90 kph.

After replacing the DC7107 bush kit:
- wheel alignment, wheel balancing and swap front with rear wheels (no fix)
- steering damper (no fix, but significant reduction of the vibration)
- changed front brake pads and discs (no change)
- replaced steering track rod (vibration at around 100 kph)

The vibration is now felt throughout the body. As others said here, I can see the passenger seat vibrating as well and feel it on my bum.
When replacing the track rod, tried to check for play on the steering but found no obvious signs of it. Wheels feel tight when I lift them and try to wobble around.
I expected to feel something for the swivel rods...
Could I be looking into prop shafts?
When I had the wheels lifted and span them quickly back and forth there's a huge play from the diff. I read about it and no one seems to be much worried about this... Should I?

If you get under it and twist the props back and forth by hand is there any movement from the diffs?

Does it only do it turning left?

Hi Tilo

As to the diff backlash I am not sure, I noticed the same on mine when going through various process' to sort the scary shuddering.

I have had the wobbly seat syndrome since I have had the car, again there seems to be no definitive answer, it comes on at about 63mph 2200rpm and disappears once you push through this speed rev range which suggests tyres however it doesn't come through the steering wheel.

Good luck with sorting, do please post if you find a solution

Ash

I have replaced allsorts on mine, it made it much better, but it still happens occasionally.

I have a theory, but it is only a theory.

If a non- return valve in the air suspension system was faulty, could it cause the sort of air movement that would create this extreme shaking - like simple harmonic motion.

merlinpjl said:

I have replaced allsorts on mine, it made it much better, but it still happens occasionally.

I have a theory, but it is only a theory.

If a non- return valve in the air suspension system was faulty, could it cause the sort of air movement that would create this extreme shaking - like simple harmonic motion.

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Air suspension should not be moving air under the circumstances when the wobble happens and air to the bags is controlled by the solenoid valves which are straight ON/OFF valves.
One poster has the same problem on springs.
Bang goes the theory as they say

merlinpjl said:

I have replaced allsorts on mine, it made it much better, but it still happens occasionally.

I have a theory, but it is only a theory.

If a non- return valve in the air suspension system was faulty, could it cause the sort of air movement that would create this extreme shaking - like simple harmonic motion.

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Mine is on steel springs...

Grrrrrr said:

If you get under it and twist the props back and forth by hand is there any movement from the diffs?

Does it only do it turning left?

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I didn't try that on the prop shafts. Tomorrow I'll be sending the car for the wheel alignment again and I'll check it then.

About the vibration, it's not like before. There's been improvement. Now it's constant regardless of the direction (as far I can tell) and at higher speed than before. I've only driven a few Km though. Tomorrow I'll be driving it longer, I'm sure I'll be able to test it properly.

AP90 said:

Hi Tilo

As to the diff backlash I am not sure, I noticed the same on mine when going through various process' to sort the scary shuddering.

I have had the wobbly seat syndrome since I have had the car, again there seems to be no definitive answer, it comes on at about 63mph 2200rpm and disappears once you push through this speed rev range which suggests tyres however it doesn't come through the steering wheel.

Good luck with sorting, do please post if you find a solution

Ash

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I feel your pain!
Will do... If I ever get it sorted.

AP90 said:

Hi Tilo

As to the diff backlash I am not sure, I noticed the same on mine when going through various process' to sort the scary shuddering.

I have had the wobbly seat syndrome since I have had the car, again there seems to be no definitive answer, it comes on at about 63mph 2200rpm and disappears once you push through this speed rev range which suggests tyres however it doesn't come through the steering wheel.

Good luck with sorting, do please post if you find a solution

Ash

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What wheels do you have fitted?

wammers said:

What wheels do you have fitted?

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Square ones by the sound of things:bounce:

wammers said:

What wheels do you have fitted?

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Hi Tony

18inch hurricanes with Pirelli scorpions

AP90 said:

Hi Tony

18inch hurricanes with Pirelli scorpions

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Are they P38 wheels or from a L322? If they are from an L322 do you have spigots fitted?

wammers said:

Are they P38 wheels or from a L322? If they are from an L322 do you have spigots fitted?

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I'm not sure but they match the original spare wheel which came with the car, but no spigots fitted

They are this style,

Well folks, I'm at the point of :crazy::boom:

Like I said, yesterday, after replacing the front brakes and the track rod went for a quick drive just to make sure everything was ok and I could feel the vibration coming in at around 100 kph.

So this morning, got in the car for a 50 Km drive to work, mostly highway.
Here's what's happening...

The vibration seems to randomly appear but always at 100"ish" kph speeds. If I go over or slow down, it stops and everything is smooth.
Now, I might be going crazy but I would swear it comes in between curves... I mean, after each curve and coming to a straight sometimes the car would vibrate and sometimes not.

One other thing I've noticed was that if the curve was long enough, the vibration would come for a few seconds and then go away while on the same turn.

Could it be a bad wheel balancing and the vibration being triggered by different wheel speeds to a particular combination of the wheel position where they get imbalanced!? Flat spots? Bent rims?

AP90 said:

I'm not sure but they match the original spare wheel which came with the car, but no spigots fitted

They are this style,

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Do they fit snugly on the hub? The L322 has a larger hub boss so the wheels have a larger centre diameter. That is what you need to be measuring. IF you have any L322 wheels fitted without spigot rings the wheels will not be central about their axis. Running like that will cause what you have. Worth checking.